Most DNA research focuses on genes that contain encrypted messages for making proteins, the cellular workhorses essential to life. Yet as little as 1 percent of the 3 billion chemical letters that spell out our genetic code perform that function. Everything else is commonly referred to as junk DNA, and geneticists have long puzzled over why it exists. Last June Harvard biologists Fred Winston, Lisa Laprade, and Joseph Martens reported finding a new gene in baker’s yeast that may help solve the mystery.
The gene, known as SRG1, makes ribonucleic acid, or RNA—an important middle step in protein production—but it does not produce proteins. Instead, it controls another gene in a way never seen before. While a conventional gene’s RNA serves as a blueprint for protein, SRG1 fervently spits out many useless copies of RNA, which effectively stop a nearby gene in its tracks. “It’s like Boston after a Red Sox game,” says Winston. “All the cars are barreling down the highway, and another car can’t get on at the entrance ramp because there is too much traffic.”
Martens suggests that the discovery of a new type of gene in largely ignored nether regions of DNA means that the secrets of the genome are far from known. “Sequences between [conventional genes] may have important functions that we don’t know about yet,” he says. “This is one example.”
